1 files changed, 76 insertions, 0 deletions
diff --git a/module/system/vm/trace.scm b/module/system/vm/trace.scm
new file mode 100644
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+++ b/module/system/vm/trace.scm
@@ -0,0 +1,76 @@
+;;; Guile VM tracer
+
+;; Copyright (C) 2001, 2009 Free Software Foundation, Inc.
+
+;;; This library is free software; you can redistribute it and/or
+;;; modify it under the terms of the GNU Lesser General Public
+;;; License as published by the Free Software Foundation; either
+;;; version 3 of the License, or (at your option) any later version.
+;;;
+;;; This library is distributed in the hope that it will be useful,
+;;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+;;; Lesser General Public License for more details.
+;;;
+;;; You should have received a copy of the GNU Lesser General Public
+;;; License along with this library; if not, write to the Free Software
+;;; Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+
+;;; Code:
+
+(define-module (system vm trace)
+  #:use-module (system base syntax)
+  #:use-module (system vm vm)
+  #:use-module (system vm frame)
+  #:use-module (ice-9 format)
+  #:export (vm-trace vm-trace-on vm-trace-off))
+
+(define (vm-trace vm objcode . opts)
+  (dynamic-wind
+      (lambda () (apply vm-trace-on vm opts))
+      (lambda () (vm-load vm objcode))
+      (lambda () (apply vm-trace-off vm opts))))
+
+(define (vm-trace-on vm . opts)
+  (set-vm-option! vm 'trace-first #t)
+  (if (memq #:b opts) (add-hook! (vm-next-hook vm) trace-next))
+  (set-vm-option! vm 'trace-options opts)
+  (add-hook! (vm-apply-hook vm) trace-apply)
+  (add-hook! (vm-return-hook vm) trace-return))
+
+(define (vm-trace-off vm . opts)
+  (if (memq #:b opts) (remove-hook! (vm-next-hook vm) trace-next))
+  (remove-hook! (vm-apply-hook vm) trace-apply)
+  (remove-hook! (vm-return-hook vm) trace-return))
+
+(define (trace-next vm)
+  (define (puts x) (display #\tab) (write x))
+  (define (truncate! x n)
+    (if (> (length x) n)
+      (list-cdr-set! x (1- n) '(...))) x)
+  ;; main
+  (format #t "0x~8X  ~16S" (vm:ip vm) (vm-fetch-code vm))
+  (do ((opts (vm-option vm 'trace-options) (cdr opts)))
+      ((null? opts) (newline))
+    (case (car opts)
+      ((:s) (puts (truncate! (vm-fetch-stack vm) 3)))
+      ((:l) (puts (vm-fetch-locals vm))))))
+
+(define (trace-apply vm)
+  (if (vm-option vm 'trace-first)
+    (set-vm-option! vm 'trace-first #f)
+    (let ((chain (vm-current-frame-chain vm)))
+      (print-indent chain)
+      (print-frame-call (car chain))
+      (newline))))
+
+(define (trace-return vm)
+  (let ((chain (vm-current-frame-chain vm)))
+    (print-indent chain)
+    (write (vm-return-value vm))
+    (newline)))
+
+(define (print-indent chain)
+  (cond ((pair? (cdr chain))
+	 (display "| ")
+	 (print-indent (cdr chain)))))